It is common in the art for unsterile cameras used in surgical procedures to be enclosed by some type of sterile drape. The sterile drape allows the camera to be coupled with an endoscope or other surgical device without compromising operating room sterility. Most commonly, the prior art discloses surgical drapes which are made of a single type of material, such as polyethylene, with a window located at the distal end where a camera coupler is positioned and couples to the endoscope. One major disadvantage with devices of this type is that it is extremely difficult to obtain the proper alignment of the drape between the camera coupler and the endoscope to ensure an optically clear path. The drape can become folded or otherwise caught in the connection between the camera coupler and endoscope thus blocking the window and obstructing the optical path. Also, polyethylene and other similar materials do not stretch without permanent deformation, thus compromising the integrity of a sterile drape made of such material. That is, adjustments in aligning the window with the optical path can result in a tear or other damaging deformation of the drape. Additionally, because of the difficulty in obtaining proper window alignment, excessive handling by operating room personnel may ensue causing inadvertent contamination of the sterile endoscope or sterile drape.
Another common shortfall in the prior art is that the conventional window is not made of a high quality, optically clear material. Additionally, such windows generally transmit laser light effectively, resulting in projection of high intensity laser light onto the CCD image sensor of the camera. This laser light can be of such high intensity that it can "blank out" a video screen used to view the surgical area. Use of laser energy for coagulation and cutting thus creates a need for some type of band pass filter on the window to filter out undesirable wavelengths of light.
Typical of the prior art devices include U.S. Pat. No. 5,274,500 to Dunn which teaches a surgical drape for a video camera device providing a sealed, sterile encasement of the camera and its associated transmission cables. This device includes a flexible tubular member and a distal end including a lens which allows the camera to be optically coupled with an endoscope.
U.S. Pat. No. 5,078,483 to Herzberg teaches a sterile disposable camera cover made from a tubular film folded onto itself and forming a package including a plurality of folded layers. One end of the camera extends into and through an end portion of the cover so that both ends of the cover are co-located at the same side of a film package which houses the cover prior to use.
U.S. Pat. No. 5,198,894 to Hicks discloses an endoscope having a sleeve-like drape secured in a retracted position at the proximal end of the endoscope. When the endoscope is secured to a camera, the drape is extended to telescope over and envelope the camera such that the resulting outer surface of the drape in its extended position remains sterile. The drape is attached at the proximal end of the endoscope as opposed being positioned between the camera and the endoscope.
A particularly relevant prior art reference is my earlier U.S. Patent No. Re. 34,002. The invention disclosed therein includes a sterile drape which extends over the camera and its extending cables, and a connecting structure which allows the video camera to be attached to an optical connector known in the art as a "C" mount or "V" mount.
It is one primary object to provide for a sterile drape having an elastic distal segment that results in easier alignment of the window when connecting a camera to an endoscope, and prevents damage to the drape, the elastic material being able to withstand the stress of the physical connection between a camera and endoscope. It is another object of this invention to provide for a window that may be coated with a material that results in filtering certain wavelengths of light passing therethrough. These coatings are particularly important when laser light is used during the surgical procedure. It is yet another object of this invention to provide for a window being constructed of an optically clear and durable material that does not easily cloud or damage, thus enhancing the ability of light to pass undistorted therethrough.
While the prior references may be adequate for their intended purposes, none of the references show either alone or in combination the novel structure set forth below.